Abstract Detail

Accidental oil spills wash onto shore in coastal regions of North America and affect plants in salt marshes. It is hypothesized tolerance to both flooding and oil are related, as both impede gas exchange between roots and their environment. In the event of an oil spill, oil covers root tissue, inhibiting gas exchange and increasing root oxygen stress. This is similar to flooding;both reduce the availability of oxygen to a plant. To determine effects of oil on respiration and photosynthesis,individuals of native Ammophila breviligulata, Panicum virgatum, Schizachyrium littorale, Solidago sempervirens, Spartina alterniflora, Florida and New Jersey ecotypes of Spartina patens,and Spartina pectinata as well as invasive Phalaris arundinacea and Phragmites australis were subject to 6 Lm-2 light motor oil in greenhouse experiments for six weeks. Alcohol dehydrogenase activities doubled in roots of P. arundinacea, P. virgatum, S. sempervirens,the New Jersey ecotype of S.patens, and S. pectinata from oil exposure, indicating oxygen stress. Additionally, decreases in photosynthetic rates were measured in P. virgatum and the New Jersey ecotype of S. patens following oil exposure, indicating limited gas exchange. In some cases,tolerance to oil relates to flooding tolerance. Root alcohol dehydrogenase activities are a sensitive indicator of oil susceptibility. The most tolerant species under oil conditions were P. australis and S. littorale,showing little change in photosynthesis or respiration.Therefore, invasive P. australis had a higher physiological tolerance to oil compared to some natives in this study, such as S. pectinata. Pollution by oil spills could potentially favor establishment of introduced species and thus serve as a mechanism for invasion in coastal marshes.